1. Field of the Invention
This invention relates in general to sucker rod oil well pumps and in particular to hardened metal layers on the plunger and barrel.
2. Description of the Prior Art
Sucker rod well pumps have been in wide use for many years. A barrel is mounted to the tubing. The barrel has a smooth cylindrical bore. A plunger is positioned inside the tubing and connected to the sucker rod. The sucker rod is reciprocated up and down to move the plunger in the barrel. A stationary check valve is located at the bottom of the barrel. A traveling valve is located at the bottom of the plunger. The valves cooperate on the downstroke and upstroke to pump fluid from the well to the surface.
The mating surfaces between the plunger and barrel provide a very close fit. In wells which produce abrasive particles, such as quartz or sand, these particles can quickly damage the mating surfaces. The wear due to the abrasive particles will cause leakage past the plunger. This necessitates the pump being pulled for replacement at fairly frequent intervals.
Various techniques have been used in the past to increase the wear resistance. In one technique, a chrome case is plated on either of the barrel or the plunger. Circumferential grooves have also been formed in the plunger.
It is an object of this invention to provide a method for making a sucker rod well pump with increased wear resistance to abrasive particles.
It is the further object of this invention to provide a method for hardening the walls of a well pump plunger and a barrel.
It is the further object of this invention to provide a method of hardening a wall of a steel plunger for a well pump by applying a boronized case supported by a hardened steel layer.